Question

我在java中有以下类：

public class Classic {
    @Annotate1(location="foo", name="bar")
    public final Comp1 comp1 = new Comp1();

    @Annotate2(member="blessed")
    public final Comp2 comp2 = new Comp2();
}

现在，在一个单独的课程中，我可以访问Classic，Comp1和Comp2的对象。在同一个地方，我不知道Classic.中字段的名称如何获取comp1和comp2对象的注释？

Answer 1

这是一个让你入门的例子：

public class Classic {
    @Annotate1(location = "foo", name = "bar")
    public final Comp1 comp1 = new Comp1();

    @Annotate2(member = "blessed")
    public final Comp2 comp2 = new Comp2();

    public static void main(String[] args) {
        Class clazz = Classic.class;
        for(Field field: clazz.getDeclaredFields()){

            if(field.isAnnotationPresent(Annotate1.class)){
                Annotate1 annotate1 = field.getAnnotation(Annotate1.class);
                System.out.println(annotate1.name());
            }else if(field.isAnnotationPresent(Annotate2.class)){
                Annotate2 annotate2 = field.getAnnotation(Annotate2.class);
                System.out.println(annotate2.member());
            }
        }
    }
}

如果您正在制作自己的注释，请确保将它们设置为在运行时保留：

@Retention(RetentionPolicy.RUNTIME)  //Important
public @interface Annotate1 {

    String name();

    String location();

}

获取类中特定对象的注释

1 个答案: